Fix a timing bug in multibuffer.

media/blink/multibuffer_data_source.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BLINK_MULTIBUFFER_DATA_SOURCE_H_
 #define MEDIA_BLINK_MULTIBUFFER_DATA_SOURCE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 153 matching lines @@
 
   // Check if we've moved to a new url and update has_signgle_origin_.
   void UpdateSingleOrigin();
 
   // MultiBufferReader progress callback.
   void ProgressCallback(int64_t begin, int64_t end);
 
   // call downloading_cb_ if needed.
   // If |force_loading| is true, we call downloading_cb_ and tell it that
   // we are currently loading, regardless of what reader_->IsLoading() says.
-  void UpdateLoadingState(bool force_loading);
+  // Caller must hold |lock_|.
+  void UpdateLoadingState_Locked(bool force_loading);
 
   // Update |reader_|'s preload and buffer settings.
   void UpdateBufferSizes();
 
   // crossorigin attribute on the corresponding HTML media element, if any.
   UrlData::CORSMode cors_mode_;
 
   // URL of the resource requested.
   scoped_refptr<UrlData> url_data_;
 
@@ skipping 83 matching lines @@
   // reaching into this class from multiple threads to attain a WeakPtr.
   base::WeakPtr<MultibufferDataSource> weak_ptr_;
   base::WeakPtrFactory<MultibufferDataSource> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MultibufferDataSource);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BLINK_MULTIBUFFER_DATA_SOURCE_H_